The use of utility pull boxes for power feed and distribution purposes is pervasive. Such pull boxes are generally located underground at the "grade" level and they are used for accommodating distribution and/or feeder class power cables so as to allow such cables to be removed in the event of an interruption in power service.
Prior art pull boxes are generally cubicle in form. The distribution or feeder cables enter the interior of the prior art pull box through its bottom and each of the three wires associated with each power cable is attached to a different buss, each of the required busses being located on respective different walls of the pull box. The covers for such pull boxes are rectangular and the lid mounted in the central portion of the cover is usually rectangular.
However, there are inherent disadvantages present in association with present utility pull boxes. Initially, the power cables that enter the interior of the boxes are unwieldy and such cables have a large bending radius recommended by the cable manufacturer. Likewise, since there are a number of overlapping cables within the box, when the cables are connected to the respective busses, it can be dangerous to remove a cable from the buss within the box without risking the accidental removal of adjacent cables from their respective busses. This is so because the movement of one cable may cause dislodgement of a further cable and such dislodgement may result in a live power cable being uncontrolled within the box.
A further disadvantage relates to pulling the cables to the box. In previous boxes, the cables must be bent 90 degrees when approaching and entering the box. Such a significant turn produced a great deal of side wall friction being generated between the cable and the duct through which the cable is pulled. This can result in destruction of the duct and destruction of the cable.
A further disadvantage related to the lid used for the cover of previous utility pull boxes. If the lid was rectangular in form and because the lid is heavy, it could be inadvertently dropped into the box and thereby detach the cables mounted therein. Again, a dangerous condition was created.
Yet a further disadvantage inherent in present utility pull boxes relates to the movement of the cables within the interior of the utility box. The manufacturers of such cables specify a minimum radius for the bending of such cables and a smaller radius for such bending can adversely affect the life and performance of the cables. In utility pull boxes in present use, the cables may be required to exceed the radius dimension specified by the manufacturer because of the difficulty in distributing such cables to their respective busses.